1. Field
The present embodiments relate to a thin magnetic film capable of suppressing short circuits between coil conductor parts, and filling the gaps of the coil conductor parts properly with an insulating layer.
2. Related Art
In the Patent Documents described below, there is disclosed a thin film magnetic head in which any magnetic pole portion is formed on the side of a surface facing a recording medium on a lower core layer. A connecting portion is formed on a height side on the lower core layer. A coil layer is formed on the lower core layer between the magnetic pole portion and the connecting portion through an insulating base layer. A gap between the magnetic pole layer and the connecting portion is magnetically connected at an upper core layer.
For example, with regard to a configuration of FIG. 2 of JP-A-2001-110014 (U.S. Pub. No. 2004/0070874 A1), which is described in [0080]˜[0081] of JP-A-2001-110014 (US Pub. No. 2004/0070874 A1), it is preferable that the upper surface of the coil insulating layer 15 is flush with the upper surface of the coil layer 17. To make the upper surface of the coil insulating layer 15 and the upper surface of the coil layer 17 flush with each other, the CMP process, for example, may be used to etch the upper surface of the coil insulating layer 15 and the upper surface of the coil layer 17.
As shown in FIG. 2 of JP-A-2001-110014 (US Pub. No. 2004/0070874 A1), the thin film magnetic head has a structure that has an upper surface of a recording portion 14 and an upper surface of a layer formed on a height side of the recording portion 14 and are in one plane. It is preferable that the upper surface of a coil layer 17 is coplanar to the upper surface of the recording portion 14 in order to maximize the thickness of the first layer (lower layer side) of the coil layer 17. For this reason, the coil layer 17 shall be formed as high as an equivalent degree to the recording portion 14, using CMP process. The process comprising grinding the coil layer 17 together with the recording portion 14, and making the upper surface of the coil layer 17 and the upper surface of the recording portion 14 coplanar to each other. A film width of the coil layer 17 can be formed in the maximum, and a coil resistance of the coil layer can be lowered.
The lowering of the coil layer is preferable that an improvement of PTP (Pole Tip Protrusion) to lower the coil resistance of the coil layer.
The coil layer is formed of soft Cu. If a coil insulating layer filling gaps of the coil conductor parts is an organic material such as a resist, since the coil layer and the coil insulating layer are soft together, a shear drop is easily formed on an upper surface of the coil conductor part (generation of smear) by a grinding process by the CMP described above. Thus, a short circuit could be generated between each coil conductor part.
When filling a gap between the coil conductor part with an inorganic insulating layer instead of the organic material, although a generation of smear could be solved since the inorganic insulating layer is hard compared to the coil conductor part, a gap of each coil conductor part cannot be filled properly with the inorganic insulating layer by sputter technique, etc. For example, a hollow portion is easily formed in the proximity of a lower edge portion of each coil conductor part, since a width between each conductor part is very narrow compared to a tall coil conductor part. If such cavity is formed, a change in a film shape inside the thin film magnetic head was caused by an expansion of gas piled up in the hollow portion due to a heat generation when a magnetic head is driven.
In JP-A-2001-052310 (U.S. Pat. No. 6,538,846 B1), for example, as shown in FIG. 2, a protection layer 27 is provided on the coil conductor part. An upper surface of this protection layer 27 corresponds to an upper surface of a track width restricting portion 14 in a plane. Providing the protection layer 27 prevents an oxidization of a coil conductor part.
In JP-A-2001-052310 (U.S. Pat. No. 6,538,846 B1), a problem of a shear drop generation of the coil conductor part described above is not recognized. A means to solve the problem is not presented, and even if the protection layer 27 was a hard material and a shear drop generation of the coil conductor part was able to be suppressed, PTP cannot be properly improved, since a manufacturing process gets complicated as an original coil layer must be plated by a two-storied laminated structure and since a coil resistance increases if the specific resistance of the protection layer 27 is high. In JP-A-2001-052310 (U.S. Pat. No. 6,538,846 B1), the coil insulating layer is mainly formed of an inorganic insulating layer, and it is formed of a structure in which the hollow portion is easily generated.